Drilax&trade; 5 Pcs Diamond Drill Bit Set 3/8", 1/2" (0.5 In), 5/8", 3/4", 1" Wet Use for Tiles, Glass, Fish Tanks, Marble, Granite, Ceramic, Porcelain, Bottles, Quartz - Lot 5 Diamond Coated Drills - Kitchen, Bathroom, Shower, Lamps Drilax051025 High Quality Diamond Drilling Tool Set of 5 Different Sizes: 3/8, 1/2, 5/8, 3/4, 1 Over 80% cost savings compared to big box stores. Use with standard hand or upright drillers. These tools do not have center pilot drills. There is no need for a center pilot drill. Do NOT run dry. Diamond Coated Tools will work best if you use water to keep the tools cool. Shank sizes vary, maximum shank is 1/4 - suitable for all common electric drillers.